Surface-modified metal compound particles, and method for producing surface-modified metal compound particles

Abstract

These surface-modified metal compound particles have metal compound particles the surfaces of which are modified by: at least one first carboxylic acid selected from the group consisting of a methacrylic acid, an acrylic acid, and a propionic acid; and at least one second carboxylic acid selected from the group consisting of a C6-C16 fatty acid and a C7-C32 monovalent carboxylic acid having at least one benzene ring, wherein at least a portion of the first carboxylic acid is a carboxylic acid type in which a hydrogen atom of the carboxy group is not dissociated as an ion.

The invention claimed is: 
     
       1. Surface-modified metal compound particles comprising:
 metal compound particles that are surface-modified with at least one first carboxylic acid selected from the group consisting of methacrylic acid, acrylic acid, and propionic acid, and at least one second carboxylic acid selected from the group consisting of a fatty acid having 6 to 16 carbon atoms and a monovalent carboxylic acid having at least one benzene ring and 7 to 32 carbon atoms, 
 wherein at least a portion of the first carboxylic acid is a carboxylic acid type in which a hydrogen atom of a carboxy group is not dissociated as an ion. 
 
     
     
       2. The surface-modified metal compound particles according to  claim 1 , wherein the second carboxylic acid is a carboxylate type in which a hydrogen atom of a carboxy group is dissociated as an ion. 
     
     
       3. The surface-modified metal compound particles according to  claim 1 , wherein a metal constituting the metal compound particles is at least one selected from the group consisting of zirconium and rare earths. 
     
     
       4. The surface-modified metal compound particles according to  claim 1 , wherein a metal compound constituting the metal compound particles is a metal oxide. 
     
     
       5. A method for producing the surface-modified metal compound particles according to  claim 1 , the method comprising:
 a step A of adding at least one second carboxylic acid selected from the group consisting of a fatty acid having 6 to 16 carbon atoms and a monovalent carboxylic acid having at least one benzene ring and 7 to 32 carbon atoms to metal compound particles having positive zeta potential and being dispersed in a water solvent; 
 a step B of drying a product obtained through the step A; and 
 a step C of adding at least one first carboxylic acid selected from the group consisting of methacrylic acid, acrylic acid, and propionic acid after the step B. 
 
     
     
       6. The method for producing surface-modified metal compound particles according to  claim 5 , wherein a metal compound concentration of a product after the step B is 80 wt % or less in terms of oxide.